br Today, we relive one of the biggest closing performances in Ultra history. At Ultra Music Festival 2015, Skrillex made his return and was joined by Diplo for a very special Jack Ü set! Surprise guests Justin Bieber, Diddy, Kiesza and CL accompanied the two for this spectacular finale.br br Were you there? If so, now is the time to search through all your photos and video from this moment and post them.